Agents for promoting fattening of animals and method of promoting fattening

ABSTRACT

Agents for promoting fattening of animals which contain as the active ingredient(s) at least one member selected from among acids originating in hexoses, non-toxic salts thereof and intramolecular esterification products thereof; and a method of promoting fattening by using these agents.

The application is the National Stage of International Application No.PCT/JP00/07237 filed Oct. 18, 2000 which claims the benefit ofApplication No. 11/296725 filed Oct. 19, 1999 in Japan.

TECHNICAL FIELD

The present invention relates to an agent for promoting the fattening ofanimals and to a method for promoting the fattening of animals. Moreprecisely, the invention relates to an agent for promoting the fatteningof animals, which contains, as an active ingredient, at least one ofhexose-derived acids such as typically gluconic acid, and theirnon-toxic salts and intramolecular ester compounds, and to a method ofpromoting the fattening of animals by use thereof.

BACKGROUND ART

For promoting the growth of animals such as livestock, antibiotics suchas tetracycline and avoparcin have heretofore been used by being addedto feed as fattening promoters. However, these antibiotics often induceresistant bacteria through mutation in the body of animals. In addition,they may remain in the body of animals, and the human beings who haveeaten the meat of the animals shall inevitably take the antibiotics. Asa result, the potency of antibiotics serving as medicines will bethereby lowered.

Recently, therefore, substances except antibiotics have beeninvestigated for fattening promoters for animals. For example, fumaricacid is used as a fattening promoter.

On the other hand, gluconic acid which is one typical example ofhexose-derived acids has heretofore been widely used. For example, itsintramolecular ester compound, glucono delta lactone is known as acoagulant for tofu (soybean curd); and calcium gluconate is known as acalcium supplement. In addition, sodium gluconate and potassiumgluconate have been officially approved as food additives recently andare used in various edibles (International Patent No. WO94/09650).

DISCLOSURE OF THE INVENTION

The inventors of the present invention have tried administering gluconicacid and its derivatives, which are highly safe to living bodies, toanimals and analyzing their activity to the living bodies. Havingspecifically examined their effect in the animal intestines, theinventors have found unexpectedly that they promote the growth ofspecific enterobacteria in the animals and that the thus-growingenterobacteria significantly increase the production of short-chainfatty acids which are effective for the growth of the living bodies. Inaddition, the inventors have further found that the production ofsubstances that will be harmful to living bodies is reduced oreliminated.

That is, if hexose-derived acids and their non-toxic salts andintramolecular ester compounds (hereinafter the term “hexose-derivedacids” generally includes all these compounds) are administered toanimals, Megasphaera and Mitsuokella, precisely Mesgasphaera elsdeniiand Mitsuokella multiacidus, among enterobacteria in the animals arespecifically proliferated.

On the other hand, as compared with the absence of the hexose derivedacids, the production of acetic acid, propionic acid and butyric acidwhich are short-chain fatty acids is promoted about 2 times, about 4times and about 8 times more, respectively. At the same time, theproduction of lactic acid, succinic acid, ammonia and hydrogen sulfidewhich are reported to have some negative influences such as diarrhea,digestive tract ulcers, lumen acidosis, etc. on living bodies is reducedor eliminated.

Therefore, if the hexose-derived acids are given to animals, theproduction of short-chain fatty acids is promoted in the living bodiesof the animals, and, as a result, the feed efficiency is improvedremarkably and the fattening of the animals is thereby accelerated.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph showing the results of Test Example 1.

FIG. 2 is a graph showing the results of Test Example 4.

BEST MODES OF CARRYING OUT THE INVENTION

The hexose-derived acids in the invention may be any of D-forms, L-formsor their mixtures. For example, they include saccharic acids such asglucaric acid, mannaric acid, gularic acid, idalic acid, etc.; andaldonic acids such as gluconic acid, galactonic acid, mannoic acid,talonic acid, allonic acid, etc., of which gluconic acid is especiallypreferred.

The non-toxic salts of these acids include, for example, salts thereofwith alkali metals such as sodium or potassium, salts thereof withalkaline earth metals such as calcium or magnesium, and salts thereofwith transition metals such as copper, iron or zinc, of which sodiumgluconate and calcium gluconate are especially preferred.

The intramolecular ester compounds of the acids are, for example,lactone compounds. For example, mentioned are intramolecular estercompounds of gluconic acid, such as glucono delta lactone, glucono gammalactone, of which glucono delta lactone is especially preferred.

These hexose-derived acids may be used alone or as an optionalcombination of two or more thereof.

As the short-chain fatty acids, may be mentioned fatty acids having twoto four carbon atoms such as acetic acid, propionic acid, butyric acid,isobutyric acid, valeric acid, isovaleric acid, caprylic acid, etc.Lactic acid and succinic acid which differ from these acids in theirintracorporeal absorption mechanism and in their influences on livingbodies are not included within the scope of the short-chain fatty acidsin the present invention.

The wording “improvement of feed efficiency” essentially means that evenpoorly-nutritious animal feed prepared from poor-quality cereals canattain almost the same level of fattening-promoting effect as that ofhighly-nutritious high-quality feed by addition of any of thehexose-derived acids thereto, but it also means that, when any of thehexose-derived acids is added to highly-nutritious feed, the feedattains a more elevated fattening-promoting effect.

The hexose-derived acids may be used as they are, but may be combinedwith solid or liquid vehicles well known in the art such as lactose,sucrose, glucose, corn starch, gelatin, starch, water, glycerin, fattyoil, sorbitol and the like to be used as agents for promoting thefattening of animals, agents for promoting the growth of animalenterobacteria, and agents for inhibiting the production of intracorporeal harmful substances.

These agents may be optionally mixed with ordinary additives such asantibacterial agents, antifungal agents, anthelminthics, antioxidants,dyes, flavorings, seasonings and enzymes, and may be prepared in theform of powders, dispersions, granules, liquid, tablets and the like byconventional methods.

The agents may be administered to animals as they are, or may be addedto feed or drinking water to be taken by animals. Preferably, they areblended to feed or drinking water for animals.

The feed and drinking water may be any that is ordinary used, and is notparticularly limited. Examples of the feed include corn, rice, barley,wheat, milo, soybean refuse, cereal bran, defatted rice bran, fish meal,skim milk, dry whey, oil, fat, alfalfa meal, northern-sea meal, soybeanoil and fat, dried pure beef tallow, wheat flour, rapeseed oil and fat,feather meal, animal oil and fat, calcium phosphate, corn gluten meal,molasses, corn germ meal, calcium carbonate, tricalcium phosphate,sodium chloride, choline chloride, vitamins (vitamin A, vitamin B₁,vitamin B₂, vitamin B₆, vitamin B₁₂, vitamin D, vitamin E, calciumpantothenate, nicotinamide, folic acid, etc.), amino acids (lysine,methionine, etc.), minor inorganic salts (magnesium sulfate, ironsulfate, copper sulfate, zinc sulfate, potassium iodide, cobalt sulfate,etc.), living microorganisms, etc., which may be blended and prepared asappropriate.

The dose of the hexose-derived acids varies depending on the species andthe body weight of animals to which they are applied, but generallyfalls between 20 and 1300 mg/kg/day, preferably between 20 and 600mg/kg/day. In the case where the hexose-derived acids are added to thefeed or drinking water for animals, the hexose-derived acids maygenerally be used as active ingredients in a proportion between 0.05 and2.0% by weight (“%” is hereinafter % by weight), preferably between 0.1and 1.0%.

The invention also provides a method for raising animals byadministering an agent as mentioned above to animals or by feedinganimals with feed or drinking water that contains the agent.

The method is applicable to any ordinary livestock including, forexample, cattle, pigs, horses, sheep, goats, rabbits, minks, chickens,turkeys, domestic ducks, quails, wild ducks, soft-shelled turtles,frogs, lobsters, prawns, shrimps, yellowtails, sea breams, globefishes,eels, salmon, trout, horse mackerels, etc. It is preferably appliedespecially to cattle, pigs or chickens. An agents according to theinvention and the feed or drinking water containing it may beadministered or fed to these animals in ordinary manners.

Together with the agent of the invention, enterobacteria such asMegasphaera and Mitsuokella may be administered directly to animals, forexample, in the form of a dry preparation. This is expected to furtherenhance the promotion of the growth of enterobacteria followed by thepromotion of the fattening of animals.

EXAMPLES

The invention is described in more detail with reference to thefollowing Examples, which, however, are not intended to restrict thescope of the invention.

Example 1

To a feed for pigs (Colomeal GS, a Nippai feed mixture for raisingsuckling-stage piglets, manufactured by Nippon Haigo Shiryo), added were0.0625%, relative to the weight of the feed, of sodium gluconate.

Examples 2 to 5

To the feed for pigs (Colomeal GS, a Nippai feed mixture for raisingsuckling-stage piglets, manufactured by Nippon Haigo Shiryo), added were0.125% (Example 2), 0.25% (Example 3), 0.5% (Example 4) and 1.0%(Example 5), relative to the weight of the feed, of sodium gluconate.

Comparative Example 1

The feed for pigs (Colomeal GS, a Nippai feed mixture for raisingsuckling-stage piglets, manufactured by Nippon Haigo Shiryo) itself wasused as feed.

Comparative Example 2

To the feed for pigs (Colomeal GS, a Nichihai feed mixture for raisingsuckling-stage piglets, manufactured by Nippon Haigo Shiryo), added were2%, relative to the weight of the feed, of fumaric acid (manufactured byTakeda Chemical Industries Ltd.).

Test Example 1

The feeds of Examples 1 to 5 and Comparative Examples 1 and 2 were fedto groups of piglets (about 35-day-old hybrid piglets), each group beingcomposed of 4 piglets (2 male piglets and 2 female piglets),continuously for 4 weeks. At the start of the feeding test, on two weeksafter the start of the test, and at the end of the test, that is, threetimes in all, the piglets were weighed individually, and an increase inthe body weight was calculated for each group. In each group, checkedwas the feed intake during the period between the days on which the bodyweight was measured, and the feed conversion ratio was calculated fromthe overall body weight increase and the overall feed intake. The testwas repeated 4 times, and the body weight increases and feed conversionratios obtained 4 times were averaged for every group. The results areshown in the following Table 1 and FIG. 1.

TABLE 1 Mean Body Mean Feed Amount of Amount of Weight Conversion SodiumFumaric Increase ± Ratio ± Gluconate Acid S.D. S.D. Added (%) Added (%)(index*) (index*) Example 1 0.0625 — 14.58 ± 2.42 1.78 ± 0.07 (102) (92)Example 2 0.125 — 14.50 ± 1.95 1.85 ± 0.10 (102) (95) Example 3 0.25 —14.90 ± 1.87 1.75 ± 0.05 (104) (90) Example 4 0.5 — 15.35 ± 2.26 1.69 ±0.16 (108) (87) Example 5 1.0 — 15.95 ± 2.97 1.74 ± 0.15 (112) (90)Comp. 0 — 14.28 ± 2.04 1.94 ± 0.12 Example 1 (100) (100)  Comp. — 2.014.50 ± 2.16 1.85 ± 0.06 Example 2 (102) (96) *Index based onComparative Example 1 of 100.

As shown in the results, in the cases where the piglets were fed withthe feeds that contained from 0.0625 to 1.0% of sodium gluconate, thebody weight of the piglets increased by 2 to 12% and the feed efficiencyimproved by 5 to 13%, as compared with the cases of the piglets nothaving taken sodium gluconate.

Example 6

To a feed for piglets (“Kobuta Tonton”, a feed mixture for raisingpiglets, manufactured by Nippon Haigo Shiryo), added were 0.5%, relativeto the weight of the feed, of sodium gluconate.

Example 7

To the feed for piglets (“Kobuta Tonton”, a feed mixture for raisingpiglets, manufactured by Nippon Haigo Shiryo), added were 0.5%, relativeto the weight of the feed, of glucono delta lactone.

Example 8

To the feed for piglets (“Kobuta Tonton”, a feed mixture for raisingpiglets, manufactured by Nippon Haigo Shiryo), added were 0.5%, relativeto the weight of the feed, of calcium gluconate.

Example 9

Sodium gluconate was added to and dissolved in tap water, the amount ofwhich was such that piglets drank up in 8 hours/day (9:00 to 17:00), insuch an amount that sodium gluconate could be taken by test piglets inthe same amount as taken when the feed contained 0.5% gluconate (200mg/kg-body weight/day). During the other hours, tap water not containingsodium gluconate was given. This cycle was repeated.

Comparative Example 3

The feed for piglets (“Kobuta Tonton”, a feed mixture for raisingpiglets, manufactured by Nippon Haigo Shiryo) itself was used as feed.

Test Example 2

The feeds of Examples 6 to 8 and Comparative Example 3 and the drinkingwater of Example 9 were fed to groups of piglets (about 2-month-oldter-hybrid piglets), each group being composed of 6 piglets (3 malepiglets and 3 female piglets), continuously for 8 weeks. At the start ofthe feeding test, on two weeks, 4 weeks and 6 weeks after the start ofthe test, and at the end of the test, that is, five times in all, thepiglets were weighed individually, and the body weight increase wascalculated for every group.

In each group, checked was the feed intake during the period between thedays on which the body weight was measured, and the feed conversionratio was obtained from the overall body weight increase and the overallfeed intake.

The test was repeated 3 times for Example 6, once for Example 7, oncefor Examples 8 and 9, and twice for Comparative Example 3, and theobtained body weight increases and feed conversion ratios were averagedfor every group. The results are shown in Table 2.

TABLE 2 Type of Additive, Administration Mode, and Mean Body Amount ofWeight Increase Mean Feed Additive Added (kg) Conversion Ratio (%)(index*) (index*) Example 6 sodium gluconate 38.7 (112) 2.77 (92) infeed, 0.5 Example 7 glucono delta 40.8 (118) 2.57 (86) lactone in feed,0.5 Example 8 calcium 38.2 (110) 2.75 (92) gluconate in feed, 0.5Example 9 sodium gluconate 38.2 (110) 2.87 (96) in drinking water, 0.5Comparative sodium gluconate 34.7 (100)  3.00 (100) Example 3 in feed, 0*Index based on Comparative Example 3 of 100.

As shown in Table 2, in the cases where the piglets were fed with thefeeds or the drinking water that contained 0.5% of sodium gluconate,calcium gluconate and glucono delta lactone, the body weight of thepiglets increased by 10 to 18% and the feed efficiency improved by 4 to14%, as compared with the cases of the piglets not having taken thegluconic acid derivatives.

Example 10

To a standard test feed for chickens (SDB No. 1 and SDB No. 2, standardtest feeds for broilers, manufactured by Nippon Haigo Shiryo), addedwere 0.5%, relative to the weight of the feed, of sodium gluconate.

Example 11

Since chickens drink water in an amount 3 to 4 times larger than theamount of the feed they take, 0.14% of sodium gluconate were added totap water with respect to the weight of the tap water (the amount ofsodium gluconate added thereto corresponds to 0.5% thereof added tofeed).

Comparative Example 4

The standard test feed for chickens (SDB No. 1 and SDB No. 2, standardtest feeds for broilers, manufactured by Nippon Haigo Shiryo) itself wasused as feed. Of the standard test feed for broilers, SDB No. 1 (this isfor the former stage in raising broilers) and SDB No. 2 (this is for thelatter stage in raising broilers) both contained 0.1% of sodiumgluconate.

Test Example 3

The feeds of Example 10 and Comparative Example 4 and the drinking waterprepared in Example 11 were fed to groups of new born broiler chicks(Chunky), each group being composed of 50 chicks (25 male chicks and 25female chicks), continuously for 8 weeks. At the start of the feedingtest, on two weeks, 4 weeks and 6 weeks after the start of the test, andat the end of the test, that is, five times in all, the chicks wereweighed individually, and an increase in the body weight was calculatedfor every group. In each group, checked was the feed intake during theperiod between the days on which the body weight was measured, and thefeed conversion ratio was calculated from the overall body weightincrease and the overall feed intake. The results are shown in Table 3.

TABLE 3 Amount of Mean Body Sodium Weight Increase Mean Feed GluconateAdded (g) Conversion Ratio (%) (index*) (index*) Example 10 in feed, 0.52847 (110) 2.05 (94) Example 11 in drinking water, 2597 (106) 2.03 (94)0.14 Comparative in feed, 0 2460 (100)  2.17 (100) Example 4 *Indexbased on Comparative Example 4 of 100.

As shown in Table 3, in the cases where the chicks were fed with thefeed that contained from 0.5% of sodium gluconate and the drinking waterthat contained 0.14% of sodium gluconate, the body weight of the chicksincreased by 6 to 10% and the feed efficiency improved by 6%, ascompared with the cases of the chicks not having taken sodium gluconate.

Test Example 4

To a feed for latter artificial milk suckling-stage piglets(manufactured by Nippon Kagaku Shiryo Kyokai) and to a feed for raisingpiglets (manufactured by Nippon Kagaku Shiryo Kyokai), added were 0.05,0.1, 0.25, 0.5 and 1.0%, relative to the weight of the feeds, of sodiumgluconate.

The above-mentioned feeds were fed to groups of piglets (body weight:about 20 kg), each group being composed of 4 piglets (2 male piglets and2 female piglets), continuously for 8 weeks (the feed for latterartificial milk for the former 2 weeks and the feed for raising pigletsfor the latter 6 weeks). During the period of the feeding test, each ofthe piglets was weighed every week, and an increase in the body weightwas calculated for every group. In each group, checked was the feedintake during the period between the days on which the body weight wasmeasured, and the feed conversion ratio was calculated.

This test was repeated 10 times for the group not having taken sodiumgluconate and the group having taken 0.5% sodium gluconate, but 5 timesfor the other groups having taken sodium gluconate in differentconcentrations. The obtained body weight increases and the feedconversion ratios were averaged for every group. The results are shownin Table 4 and FIG. 2.

TABLE 4 Body Weight Feed Amount of Increase Conversion Additive TestCycle (kg) ± S.D. Ratio ± S.D. Added (%) Frequency (index %) (index %)Control with — 10 38.46 ± 4.44 2.70 ± 0.14 no additive (100) (100)Sodium 0.05 5 39.96 ± 5.83 2.62 ± 0.15 Gluconate (104)  (97) Added 0.1 540.92 ± 4.49 2.58 ± 0.11 (106)  (96) 0.25 5 41.26 ± 3.44 2.55 ± 0.17(107)  (94) 0.5 10 40.43 ± 4.40 2.63 ± 0.12 (105)  (97) 1.0 5 39.28 ±2.58 2.74 ± 0.05 (102) (101)

As shown in the results, in the cases where the piglets were fed withthe feeds containing 0.05 to 1.0 wt % of sodium gluconate, the bodyweight of the piglets increased by 2 to 7%, and the feed conversionratio improved by 3 to 6%, as compared with the case where sodiumgluconate was not added to the feeds.

Example 12

Three pigs were acclimated for 1 week, and the contents of their largeintestines were taken out. The contents were diluted 5-fold with ananaerobic phosphate buffer (50 mM, pH 6.5), and then filtrated through4-layered gauze. 25 mL of the resulting filtrate was put into serumbottles of 120 mL volume, and the gas phase therein was purged with amixed gas of nitrogen/carbon dioxide (80/20). The bottles were sealedwith butyl rubber stoppers and aluminum seals, and left for staticculture at 39° C. for 24 hours (n=3).

Prior to putting the intestinal filtrate into the serum bottles, 1 w/v %glucose (positive control) and 1 w/v % sodium gluconate were put in thebottles, except for an additive-free control (negative control).

After the intestinal filtrate was thus cultivated, 1 mL of 6 Nhydrochloric acid was added thereto to stop fermentation. The resultingcultures were analyzed as follows:

The cultures were pre-treated according to the Ushida and Sakata'sconditions (Anim. Sci. Technol., 69, 571-575, 1988), and then wereanalyzed on the concentration of short-chain fatty acids, succinic acidand lactic acid therein by HPLC and the concentration of ammonia thereinby the indophenol method (Weatherburn, Analytic Chem., 39, 971-974,1967). Subtracting the concentration before cultivation from that aftercultivation gives the amount (mM) generated through fermentation. Theresults are shown in Table 5.

TABLE 5 (mM) Succinic Acid Lactic Acid Acetic Acid Propionic AcidButyric Acid Ammonia Before Cultivation 0.17 3.37 40.06 10.97 5.39 7.83(100) (100) (100) (100) (100) (100) After Cultivation Control with noadditive 0 0.16 69.27 26.08 8.97 28.81 (0) (5) (173) (238) (166) (368)Sodium Gluconate added 0 0 161.90 103.25 70.36 5.79 (0) (0) (404) (941)(1305) (74) Glucose added 1.26 58.31 119.04 111.48 35.08 4.82 (741)(173) (297) (1016) (651) (62) *The data parenthesized indicate the indexbased on the data before cultivation of 100.

As shown in Table 5, the concentration of acetic acid, propionic acidand butyric acid in the cultures with sodium gluconate added theretogreatly increased as compared with that in the cultures without sodiumgluconate. This increase is comparable or higher as compared with thecultures with glucose added thereto, and in particular, butyric acid wasobserved to increase significant. Substances which may be harmful suchas lactic acid, succinic acid and ammonia were observed to greatlyreduce in the cultures with sodium gluconate added thereto.

Example 13

The amount of fermentation gas generated in the cultivation of Example12 was measured by putting a glass syringe equipped with an injectionneedle into a head space of the serum bottle, sucking the gas untilnormal pressure is reached and measuring the sucked gas by a syringescale.

The composition of the gas was analyzed for carbon dioxide, methane,hydrogen and hydrogen sulfide by TCD and FPD gas chromatography (Ushida,et al.; Jpn. J. Zootech. Sci., 53, 412-416, 1982, and Anim. Sci.Technol., 69, 571-575, 1998). The results are shown in Table 6 (n=3,μL/g).

TABLE 6 (μL/g) Carbon Hydrogen Total Gas Dioxide Hydrogen MethaneSulfide Control 2620 420 9.84 10 3.29 with no additive Sodium 6880 4330211.99 30 0.09 Gluconate added Glucose 4800 2180 228.53 0 0.29 added

As shown in Table 6, hydrogen sulfide, a harmful substance, greatlyreduced in the cultures with sodium gluconate added thereto, as comparedwith the case of the cultures with no additives. The increased amount ofgenerated hydrogen and methane suggests active anaerobic fermentation bymicroorganisms.

Example 14

Pigs were acclimated for 1 week, and the contents of their largeintestines were taken out. The contents were diluted 5-fold with ananaerobic phosphate buffer (50 mM, pH 6.5), and then filtrated through4-layered gauze. One mL of the resulting filtrate was inoculated on aPYF medium (100 mL) with 1 w/v % sodium gluconate added thereto, andincubated in an anaerobic condition at 39° C.

During incubation, 5 mL of a sterilized 10 w/v % aqueous solution ofsodium gluconate were put into the medium at intervals of 48 hours.

The culture without sodium gluconate and the culture with sodiumgluconate added thereto were sampled on 0, 8, 24, 48, 96 and 144 hoursin a germ-free condition, and the samples were diluted to 10⁻⁵. 0.05 mLof each dilution were inoculated on BL agar media (manufactured byNissui), and anaerobically incubated at 37° C. for 48 hours. The numberof colonies of anaerobic microorganisms having grown in agar plates wascounted (Table 7).

At the same time, according to the properties of the colonies thusgrown, strains having grown only on the agar plate inoculated with the144-hour sample of sodium gluconate-added culture were isolated, andthey were counted and identified (Table 8).

TABLE 7 (data: logarithmic number of the cells in 1 g of culture) Timeafter Start of Incubation (hrs) 0 8 24 48 96 144 Control with no <6.38.3 9.3 8.3 8.4 7.4 additive Sodium <6.3 8.9 10.7 8.7 10.4 7.7 Gluconateadded

TABLE 8 (data: logarithmic number of the cells in 1 g of culture)Control with no additive Sodium Gluconate added Megasphaera elsdenii<6.3 6.4 Mitsuokella multiacidus <6.3 7.2

As shown in Tables 7 and 8, the addition of sodium gluconate increasedthe total number of anaerobic microorganisms. In particular,Mesgasphaera elsdenii and Mitsuokella multiacidus were observed toincrease.

Example 15

The strains Mesgasphaera elsdenii and Mitsuokella multiacidus havinggrown in Example 14 were anaerobically incubated in PYF media (100 mL)with 1% w/v sodium gluconate added thereto, at 39° C. for 24 hours. Thecultures were analyzed on the concentration of the short-chain fattyacids (mM) therein in the same manner as in Example 12. The results areshown in Table 9.

TABLE 9 (mM) Type of Acetic Propionic Enterobacteria Acid Acid ButyricAcid Megasphaera Control with no 5.8 1.6 1.4 elsdenii additive SodiumGluconate 8.7 0.8 4.9 added Difference 2.9 −0.8 3.5 Mitsuokella Controlwith no 2.9 7.0 0.3 multiacidus additive Sodium Gluconate 9.9 43.1 1.0added Difference 7.0 36.1 0.7

As shown in Table 9, it was confirmed that the two species ofenterobacteria utilized sodium gluconate to produce various short-chainfatty acids. In particular, Mesgasphaera elsdenii produced a lot ofacetic acid and butyric acid, and Mitsuokella multiacidus produced a lotof acetic acid and propionic acid.

The present invention provides an agent for promoting the fattening ofanimals, which contains, as the active ingredient, at least one ofhexose-derived acids and their non-toxic salts and intramolecular estercompounds and also provides a method for promoting the fattening ofanimals by use of the promoting agent.

The promoting agent increases enterobacteria, thereby inducing theproduction only of short-chain fatty acids that are useful for thegrowth of living things. Consequently, even a poorly-nutritious feed canattain the same level of feed efficiency as that of highly-nutritiousfeed, and the fattening of animals can be promoted.

What is claimed is:
 1. A method for raising an animal comprisingadministering to said animal with a feed or drinking water at least onecompound selected from the group consisting of: a hexose-derivedacid(s), a non-toxic salt(s) thereof and an intramolecular estercompound(s) thereof, wherein said at least one compound is administeredto animals in an amount of 20 to 1,300 mg/kg/day and wherein said atleast one compound promotes the growth of enterobacteria having theability to produce a short-chain fatty acid.
 2. A method for raising ananimal comprising administering to said animal with a feed or drinkingwater, at least one compound selected from the group consisting of: ahexose-derived acid(s), a non-toxic salt(s) thereof and anintramolecular ester compound(s) thereof, wherein said at least onecompound is administered to said animals in an amount of 200 to 1,300mg/kg/day, and wherein said at least one compound inhibits theproduction of an intracorporeal harmful substance.
 3. A method forraising an animal comprising administering to said animal with a feed ordrinking water at least one compound selected from the group consistingof: a hexose-derived acid(s), a non-toxic salt(s) thereof and anintramolecular ester compound(s) thereof wherein said at least onecompound is administered in an amount of 20 to 1,300 mg/kg/day, andwherein the animal is selected from the group consisting of cattle, pigsor chickens.
 4. A method for animal feeding, comprising: selecting ananimal in need of (a) fattening, (b) the promotion of the growth ofenterobacteria which produce a short-chain fatty acid, or (c) thereduction of the production of lactic acid, succinic acid, ammonia orhydrogen sulfide, administering to said animal an amount of at least onehexose-derived acid, or a salt or intramolecular ester of a hexosederived acid, in a feed or drinking water, wherein said amount iseffective to promote the fattening of said animal, effective to promotethe growth of enterobacteria which produce at least one short-chainfatty acid in said animal, or effective to reduce the production oflactic acid, succinic acid, ammonia or hydrogen sulfide in said animal.5. The method of claim 4, wherein said amount ranges from 10 to 1,300mg/kg/day.
 6. The method of claim 4, wherein said amount ranges from 20to 600 mg/kg/day.
 7. The method of claim 4, comprising selecting ananimal in need of fattening.
 8. The method of claim 4, comprisingselecting an animal in need of the promotion of the growth ofenterobacteria which produce at least one short-chain fatty acid in saidanimal.
 9. The method of claim 4, selecting an animal in need of areduction of the production of lactic acid, succinic acid, ammonia orhydrogen sulfide in said animal.
 10. The method of claim 4, comprisingadministering to said animal a saccharic acid or a salt orintramolecular ester of a saccharic acid.
 11. The method of claim 4,comprising administering to said animal an aldonic acid or a salt orintramolecular ester of an aldonic acid, which is not gluconic acid or asalt or intramolecular ester of gluconic acid.
 12. The method of claim4, comprising administering to said animal a hexose-derived acid, or asalt or intramolecular ester of a hexose-derived acid, which is selectedfrom the group consisting of glucaric acid, gularic acid, idalic acid,galactonic acid, mannoic acid, talonic acid, and allonic acid.
 13. Themethod of claim 4, wherein said hexose-derived acid, or a salt orintramolecular ester of a hexose-derived acid is gluconic acid, or asalt or intramolecular ester of gluconic acid.
 14. The method of claim4, comprising administering to said animal gluconic acid.
 15. The methodof claim 4, comprising administering to said animal a salt of gluconicacid.
 16. The method of claim 4, comprising administering to said animalan intramolecular ester of gluconic acid.
 17. The method of claim 4,comprising administering to said animal glucono delta lactone.
 18. Themethod of claim 4, comprising administering to said animal glucono gammalactone.
 19. The method of claim 4, wherein said at least onehexose-derived acid, or a salt or intramolecular ester of ahexose-derived acid, promotes the growth of enterobacteria, which areMegasphaera or Mitsuokella, which produce at least one short chain fattyacid.
 20. The method of claim 4, wherein said animal is a livestockanimal.
 21. The method of claim 4, wherein said animal is cattle. 22.The method of claim 4, wherein said animal is a chicken.
 23. The methodof claim 4, wherein said animal is a pig.
 24. The method of claim 4,wherein said at least one hexose-derived acid, or a salt orintramolecular ester of a hexose-derived acid is administered in ananimal feed.
 25. The method of claim 4, wherein said at least onehexose-derived acid, or a salt or intramolecular ester of ahexose-derived acid is administered in animal drinking water.